Nuclear Power Deployment Operation and Sustainability Part 10 pptx

Nuclear Power– Deployment, Operation and Sustainability 304 [44] Iwahori, K., F. Takeuchi, K. Kamimura and T. Sugio, "Ferrous-dependent volatilisation of mercury by the plasma membrane of Thiobacillus ferrooxidans", Applied and Environmental Microbiology 66(9), 3823-3825, 2000. [45] Kawatra S. K. and K. A.Natarjan," Mineral Biotechnology ", SME Publ. , PP. 101 – 119, 2001. [46] Brierley JA, Brierley CL., "Microbial leaching of copper at ambient and elevated temperatures", Metallurgical applications of bacterial leaching and related microbiological phenomena, Academic Press, PP. 477–490,1978. [47] G. J. Olson, J. A. Brierley, C. L. Brierley, " Bioleaching review part B: Progress in bioleaching: applications of microbial processes by the minerals industries", Appl. Microbiol Biotechnol., No.63, PP.249–257, 2003. [48] Rawlings DE, Dew D., "du Plessis C: Biomineralization of metalcontaining ores and concentrates", Trends Biotechnol, 21:38-44, 2003. 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[54] Olson GJ, Porter FD, Rubinstein J, Silver S., "Mercuric reductase enzyme from a mercury-volatilizing strain of Thiobacillus ferrooxidans", J Bacteriol, No.151,PP.1230–1236, 1982. [55] Hallberg, K.B. and E.B. Lindstrom, "Characterisation of Thiobacillus caldus sp. nov., a moderately thermophilic acidophile", Microbiology 140 (12), 3451-3456, 1994. [56] Blais, J.F., R.D. Tyagi, N. Meunier and J.C. Auclair, "The production of extracellular appendages during bacterial colonisation of elemental sulphur", Process Biochemistry 29 (6), 475-482, 1994. [57] OECD: Organization for Economic Co-operation and Development, "Consensus Ducument on Information Used in the Assessment of environmental Applications Involving Acidithiobacillus", Series on Harmonization of Regulatory Oversight in Biotechnology No. 37,PP. 16, 2006. [88] Twardowska, I., "The Role of Thiobacillus ferrooxidans in pyrite oxidation in Colliery spoil tips, I. Model investigations", Acta Microbiologica Polonica 35 (3-4), 291-303, 1986. [59] Twardowska, I., "The role of Thiobacillus ferrooxidans in pyrite oxidation in Colliery spoil tips II. Investigation of samples taken from spoil tips", Acta Microbiologica Polonica 36 (1-2), 101-107, 1987. [60] Pronk, J.T., J.C. de Bruyn, P. Bos and J.G. Kuenen, Anaerobic growth of Thiobacillus ferrooxidans. Applied Environmental Microbiology 58 (7), 2227-2230, 1992. [61] Brierley CL, Briggs AP, "Selection and sizing of biooxidation equipment and circuits. In: Mular AL, Halbe DN, Barret DJ (eds) Mineral processing plant design, practice and control", Society of Mining Engineers, Littleton, Colo., PP.1540–1568, 2002. Part 4 Advances in Nuclear Waste Management 13 Storage of High Level Nuclear Waste in Geological Disposals: The Mining and the Borehole Approach Moeller Dietmar and Bielecki Rolf University of Hamburg / German Czech Scientific Foundation (WSDTI) Germany 1. Introduction Nuclear energy is the energy in the nucleus, the core of an atom. Atoms itself are tiny partic- les of the universe. Nuclear energy can be used to generate electricity in nuclear power plants which currently satisfies about 35% of the European Unions’ electrical energy needs. As of January, 2011 there is a total of 195 nuclear power plant units (including the Russian Federation) with an installed electric net capacity of 170 Giga Watt (GW) in operation in Europe and 19 units with approximately 17 GW are under construction in six countries [ENS, 2011]. Nuclear power can be generated from the fission of uranium, plutonium or thorium and by the fusion of hydrogen into helium. In nuclear fission, atoms are split apart to form smaller atoms, releasing energy which is used to produce electricity. Today it is almost all uranium. Uranium is non-renewable. It is a common metal found in rocks all over the world. Natural uranium is almost entirely a mixture of two isotopes, U-235 and U-238. Digging natural uranium U-235 must be extracted and processed to fission in a reactor. Compared with U-235, U-238 cannot fission to a significant extent. Natural uranium is 99.3 per centum U-238 and 0.7 per centum U-235. Therefore, nuclear power plants use enriched uranium in which the concentration of U-235 is increased from 0.7 per centum U-235 about 4 to 5 per centum U-235. This enrichment is expensive and done in a specific separation plant. The U-235 used in today’s reactors seems to be available from natural uranium for a number of decades. But the key energy fact is that fission of an atom of uranium liberates about 10 million times as much energy as does the combustion of an atom of carbon from coal [McCarthy, 1995]. Nuclear power plant reactors contain a core with a large number of fuel rods. Each of which is filled with pellets of uranium oxide, an atom of U-235 fissions when it absorbs a neutron. The fission produces two fission fragments and other particles that fly off at high velocity - about 80 per centum of the neutron absorptions in U-235 result in fission; the other 20 per centum are just (n, gamma) reactions, resulting in just another gamma flying about. When they stop the kinetic energy is converted to heat [McCarthy, 1995]. The heat from the fuel rods is absorbed by water which is used to generate steam to drive the turbines that generate the electricity. The steam withdrawn and run through the turbines controls the power level of the nuclear power plant reactor. Hence, nuclear power plants use nuclear fis- sion for producing electrical energy. Nuclear Power – Deployment, Operation and Sustainability 308 Electricity generated in nuclear power plants does not produce polluting combustion gases like traditional coal and/or gas power plants, an important fact that plays a key role helping to reduce global greenhouse gas emissions and tackling global warming especially as elec- trical energy demand rises in the years ahead. Hence, nuclear power is back in favor, at least in political circles. Worldwide are 436 nuclear power plants in operation, and 47 under construction. 133 nuclear power plants are planned, and 282 are proposed. In total 898 nuclear power plants will run in the near future worldwide. This could be assumed as an ideal win-win situation, but the other site of the coin is that the production of high-level nuclear waste (HLW) outweighs this advantage. Therefore, management and disposal of ra- dioactive waste became a key issue for the continued and future use of nuclear power plants in the EU. Because the safe and sustaining disposal of HLW is not solved yet, of high political and public concern, and part of international research programmes. Thus the objective of this chapter is to highlight the state-of-the-art of possible concepts for safe and sustaining storage of HLW in geological disposals that are exist, are under construction, and/or under discussion. 2. Nuclear waste Nuclear waste is a specific type of waste that contains radioactive chemical elements that do not have any practical purpose. Nuclear waste is produced as by-product of a nuclear pro- cess like nuclear fission in nuclear power plants, the radioactive left over from nuclear research projects, and nuclear bomb production. But the largest source of nuclear waste is naturally occurring radioactive material as isotopes such as carbon-14, potassium-40, uranium 238, and thorium-232. If these radioactive elements are concentrated they may become highly enriched to be treated as nuclear waste. In general nuclear waste is divided into low, medium, and high-level waste by the amount of radioactivity the waste produces. The majority of nuclear waste belongs to the so called low-level nuclear waste (LLW) which has a low level of radioactivity per mass or volume. This type of waste is all-around, and can be estimated to be approximately 80 per centum of the overall nuclear waste. It often consists of items that are only slightly contaminated but still dangerous due to radioactive contamination of a human body through ingestion, inhalation, absorption, or injection. Hence, it should not be handled by anyone without training. LLW usually includes  material used to handle the highly radioactive parts of nuclear reactors such as cooling water pipes and radiation suits, etc.,  low level radioactive waste from medical procedures in diagnosis and treatments or x- rays,  industrial waste which may contain , , or  emissions,  earth exploration in order to find new sources of petroleum,  industrial production like producing plastics,  agricultural products, most notably for the conservation of foodstuffs, etc. Not only LLW is still dangerous for the human body, also low-level radioactive material. Opposite to LLW nuclear power plants produce high-level nuclear waste (HLW) in their core that averages approximately 20 per centum of the total of nuclear waste. This waste depends on the rods (fuel elements) which includes large quantities of high level radioactive fission products and is generating heat. Also their extremely long half-live-time transuranic fragments (longer than 500,000 years) create extreme long time periods before the nuclear waste will settle to safe levels of radioactivity. Therefore, this nuclear waste at the very first is put in an intermediate and/or temporary storage facility, under strict safety conditions. Storage of High Level Nuclear Waste in Geological Disposals: The Mining and the Borehole Approach 309 This facility normally is a large storage reservoir, a so called wet storage device, located next to the reactor. The wet storage reservoir is not filled with ordinary water but with boric acid, which helps to absorb some of the radiation given off by the radioactive nuclei inside the spent fuel elements. Within this large wet storage reservoir the high-level radioactive isotopes become less radioactive due to their decay and also generate less and less heat. Hence, the final disposal of HLW is delayed to allow its radioactivity to decay. Forty years after removal from the reactor less than one thousandth of its initial radioactivity remains, and it is much easier to handle. Thus canisters of vitrified waste, or spent fuel elements assemblies, are stored in large wet storages in special ponds, or in dry concrete structures or casks for at least this length of time. But this requires specific methods to handle the HLW. Some of the methods being under consideration include short term storage, long term storage, and transmutation. The longer the spent fuel element is stored in the intermediate storage facility, the easier it will be to handle. But many nuclear power plants have been holding spent fuel elements for so long that their reservoirs are getting full. They must either send the spent fuel elements off or enlarge their wet storage reservoirs to make room for more spent fuel elements. As the wet reservoirs are filled up a major problem occur. If the spent fuel elements are placed too close together, the remaining nuclear fuel could go critical, starting a nuclear chain reaction. Therefore, another method of temporary storage is used because of the overcrowding of wet reservoirs, which is the dry storage reservoir. The dry storage reservoir accommodates the HLW and putting it in reinforced casks or entombing it in concrete bunkers. This is after the HLW has already spent about 5 years cooling in a wet storage reservoir. The dry casks reservoirs are also usually located close to the reactor site. But for long-lived and HLW it is usually envisaged that this waste has to be placed in a final disposal facility, whatever this connoted. From the political perspective it seems there is no immediate economic, technical or environmental need to speed up with the construction of final geological disposal facilities for radioactive waste. Because the European Commission has prolonged the time schedule for their member states to develop their sustainable permanent HLW disposal facilities, which first were terminated for 2018. But now the year is 2030. With this in mind and from a sustainable development perspective – and if we do not want to pass the burden finding a permanent repository solution for HLW on the future generations – it has to be noticed that the temporary storage of HLW today is clearly not a satisfactory solution which with we can proceed for longer. 3. Options for disposing nuclear waste The basic idea in long-term storage of HLW that is currently preferred by international experts consists of placing the waste in a depth of at least 500 metres below the surface in a stable geological setting, that has maintained its integrity, and will maintain its integrity for millions of years. The ambition is to ensure that the HLW will remain undisturbed for the few thousand years needed for their levels of radioactivity to decline to the point where they no longer represent a danger to present and future generations. The concept of deep geolo- gical disposal is not new, it is more than 40 years old, and the technology for building and operating such repositories is now mature enough for use. As a general concept, the natural security afforded by the chosen geological formation is enhanced by additional precautionary measures. The wastes deposited are vast immobilised in an insoluble form, in blocks of glass for example [Donald, 2010; Lutze, 1988; Weber et al., 1995], and then placed inside corrosion-resistant containers. Spaces between waste packages Nuclear Power – Deployment, Operation and Sustainability 310 are filled with highly pure, impermeable clay, and the repository may be strengthened by means of concrete structures. These successive barriers are mutually reinforcing and ensure that radioactive waste can be contained over the very long term. The main reason for relying on the deep geological disposal concept is based on the assumption that a geological environment is an entirely passive disposal system with no requirement for continuing anthropogenic involvement for its safety. It is assumed that it can be abandoned after closure with no need for continuing surveillance and monitoring. Thus, the safety of the deep geological repository system is based on multiple barriers, both engineered and natural, the main one being the geological barrier itself [OECD-NEA, 2003; Rao, 2001]. One option of disposing HLW which meets the above condition is the concept of a geological repository in the deep ocean floor, which is called seabed disposal [Carney, 2001]. It includes burial beneath a stable abyssal plain and burial in a subduction zone that slowly carry waste downward into the Earth's mantle. These option is currently not being seriously considered because of technical considerations, legal barriers in the Law of the Sea, and because in North America and Europe sea-based burial has become taboo from fear that such a repository could leak and cause widespread contamination [Nadis, 1996]. Another option of disposing HLW based on the above condition is the land-based waste disposal method of a geological repository in the deep rock, which is called the rock bed disposal. This repository concept can be realized as mined [Alexander, 2007; Loon, 2000; Miller, 2000] or borehole disposal [Anderson, 2004; Brady, 2009; Gibb, 1999; Gibb, 2005]. These repositories require as an essential boundary condition the option of recovering nuclear waste from the deep geological disposal during the initial phase of the repository, and during subsequent phases, which results in increased cost. But recovering nuclear waste provides a certain degree of freedom of choice to future generations to change waste mana- gement strategies if they wish or if there is a need for. Based on the state-of-the-art in science and engineering [IAEA, 2001] geological repositories must be designed in such a way that it can be assumed that no radioactivity will reach the Earth's surface. Hence, environmental impact assessments must cover a 10,000 years analysis for worst-case scenarios, including geological and climate changes and inadvertent anthropogenic intrusion. These assessments maintain that even under those conditions the impact on the environment would be less than current regulatory limits, which in general are lower than natural [IAEA, 2006]. In 2007 a symposium on “Safety Cases for Deep Geological Disposal of Radioactive Waste: Where Do We Stand?” [OECD_NEA, 2007] was organized by the Nuclear Energy Agency (NEA) of the Organization for Economic Co- operation and Development (OECD), in co-operation with the European Commission (EC) and the International Atomic Energy Agency (IAEA) to share experiences on  developing and documenting a safety case both at the technical and managerial levels,  regulatory requirements and expectations of the safety case,  progress made in the last decade, the actual state of the art and the observed trends,  international contributions in this field. Beside the existing concepts of man-made geological disposal facilities for long-lived waste another optional solution is to reduce the mass of long-lived, high-level waste using a technique known as partitioning and transmutation. Transmutation involves isolating the transuranic elements and long-lived radionuclide’s in the radioactive waste and aims at transforming most of them by neutron bombardment into other non-radioactive elements or into elements with shorter half-lives. The governments in some countries are investigating this option but it has not yet been fully developed and it is not clear whether it will become Storage of High Level Nuclear Waste in Geological Disposals: The Mining and the Borehole Approach 311 available on a large scale. This is because in addition to being very costly, partitioning and transmutation makes fuel elements handling and reprocessing more difficult, with potential implications for safety. Cost is an important issue in radioactive waste management as related to sustainable development. If the nuclear industry did not set aside adequate funds, a large financial burden associated with plant dismantling and radioactive waste disposal would be passed on to the next generations. Henceforth, in most of the OECD countries, the costs of dismantling nuclear power plants and of managing long-lived wastes are already included in electricity generating costs and billed to end consumers; in other words, they are internalised. Although quite high, in absolute terms, these costs represent a small pro- portion – less than 5 per centum – of the total cost of nuclear power generation. Today different waste management and disposal strategies exist which deal with all types of radioactive waste originating in particular from the operation of nuclear power plants and back end nuclear fuel element cycle facilities. Short-lived low and intermediate level radioactive waste, generated comparatively in large volumes, have meanwhile successfully been managed from the disposal perspective world-wide. But high level radioactive waste disposal is an unsolved problem today. Worldwide it is accepted and a consensus view to dispose HLW in deep geological formations for long term and safe radioactive waste management [IAEA, 2006]. On the one hand the depth for geological disposal of nuclear waste is seen several hundred meters’ below the surface in a mine, which is deemed as mi- ned disposal concept. On the other hand the depth for a disposal zone is seen in much deeper depth. This depth can become achievable through boreholes in 1 to 6 kilometers’ underground, in hard rock, which is deemed as borehole disposal concept in nuclear waste management [Brady, 2009]. 4. National management plans disposing nuclear waste The ultimate disposal of vitrified wastes, or of spent fuel elements without reprocessing, re- quires their isolation from the environment. The most favoured method is burial in dry, stable geological formations some 500 metres deep. Several countries in Europe, America and Asia are investigating sites that would be technically and publicly acceptable. But no country has yet established a workable, permanent and safe storage site for HLW or even a successful interim storage policy in place. A good overview on national HLW management plans can be found in [Wiki, 2011-1], to which is referred in the following paragraph, partly literally. The United States has 104 civilian nuclear reactors in operation today, generating approximately 20 per centum of the total electricity. Beside the 104 existing nuclear reactors 1 nuclear reactor is under construction and 11new nuclear reactors are on the immediate horizon. Nuclear fuel and HLW is currently stored in the U.S. federal states at 126 sites around the nation. In 1978 the U.S. Department of Energy (DoE) began studying Yucca Mountain, Eureka County, Nevada, to determine whether or not it would be suitable for the nation's first long-term (final) geologic repository for spent nuclear fuel and HLW. Yucca Mountain is located in a remote desert on federally protected land within the secure boun- daries of the Nevada Test Site in Nye County, Nevada. The depth of the nuclear geological waste repository will be between 200 and 425 m under surface. The host rock is volcanic tuff. Signing the Joint Resolution 87 on July 23, 2002, allow the DoE to take the next step in establishing a safe repository in which to store the United States nuclear waste. The DoE is preparing an application to obtain the Nuclear Regulatory Commission license to proceed Nuclear Power – Deployment, Operation and Sustainability 312 with construction of the repository. If the DoE receives a license from the U.S. Nuclear Re- gulatory Commission to build and operate a repository at Yucca Mountain, Nevada, it will begin shipping nuclear waste from commercial and government-owned sites to the repository sometime after 2017. But this opening date of 2017 is a best-achievable schedule because the Yucca Mountain is years behind schedule, and according to a new economic analysis, its construction may cost more than $50 Billion. For Yucca Mountain it is planned to use underground cavities with a connecting gallery to build up the log-term geologic repository storing the casks in horizontal galleries. The effectiveness of different technical barriers is under investigation. But the potential risk of this long-term geological repository can be seen by future trends in the global climate and earth quakes. Because it is not possible for computer models to precisely replicate all conditions of a realistic disposal facility. Thus the staffs of the U.S. Nuclear Regulatory Commission (NRC) use abstraction to simplify the information to be considered in a performance assessment. The degree of abstraction has to reflect the need to improve reliability and reduce uncertainty. Nonetheless, it is important for the model to be sufficiently detailed to ensure that it yields valid results for the performance assessment. Hence, a suitable model is a compromise between mathematical difficulties attached to complicated equations and the accuracy in the final result. In general, there are two different approaches to obtain a model of a realistic disposal facility: 1. Deductive or theoretical approach, based on the derivation of the essential relations of the disposal facility 2. Empirical or experimental approach, based on experiment on the disposal facility Practical approaches often use a combination of both approaches, which might be the most advantageous way to precisely replicate conditions of a realistic disposal facility. However, the Yucca Mountain project [Mascarelli, 2009; YUCCA, 2008] was widely opposed, with some major concerns being long distance transportation of waste from across the United States to this site, as well as the possibility of accidents, and the uncertainty of success in isolating nuclear waste from the human environment in the long term range. Yet, in 2009, the Obama Administration rejected use of the site in the United States Federal Budget proposal, which eliminated all funding except that needed to answer inquiries from the NRC (Nuclear Regulatory Commission), “while the Administration devises a new strategy toward nuclear waste disposal” [OMB, 2010]. On March 5, 2009, the Energy Secretary told in a Senate hearing "the Yucca Mountain site no longer was viewed as an option for storing reactor waste.”[Hebert, 2009]. As with many countries with a significant nuclear power program, the 18 operating nuclear power plants in Canada generated about 16 per centum of its electricity in 2006; Canada has focussed its research and development efforts for the long-term management of HLW on the concept of deep geological disposal. In 1975 the Canadian nuclear industry defined its waste-management objective as to " isolate and contain the radioactive material so that no long term surveillance by future generations will be required and that there will be negligib- le risk to man and his environment at any time. Storage underground, in deep imperme- able strata, will be developed to provide ultimate isolation from the environment with the minimum of surveillance and maintenance.” [Dyne, 1975]. In 1977 a Task Force commissio- ned by Energy, Mines and Resources Canada concluded that interim storage was safe, and recommended the permanent disposal of used nuclear fuel in granites’, with salt deposits as a second option [Hare, 1977]. This recommendation was echoed shortly afterward by a concurrent Royal Commission on Electric Power Planning [Porter, 1978; Porter, 1980]. Many European countries have studied the deep disposal of HLW concept for a long time. In 1983, the Finnish government decided to select a site for permanent repository by 2010. Storage of High Level Nuclear Waste in Geological Disposals: The Mining and the Borehole Approach 313 With four nuclear reactors providing 29 per centum of its electricity, Finland in 1987 enacted a Nuclear Energy Act making the producers of radioactive waste responsible for its disposal, subject to requirements of its Radiation and Nuclear Safety Authority and an abso- lute veto given to local governments in which a proposed repository would be located. The Finnish Parliament approved the deep geologic repository Onkalo in igneous bedrock at a depth of about 500 meters in 2010, a huge system of underground tunnels that is being hewn out of solid rock and must last at least 100,000 years [Ford, 2010]. The repository concept is similar to the Swedish model, with containers to be clad in copper and buried below the water table beginning in 2020. In Sweden there are ten operating nuclear reactors that produce about 40 per centum of Sweden’s electricity. The responsibility for nuclear waste management has been transferred in 1977 from the government to the nuclear industry, requiring reactor operators to present an acceptable plan for waste management with a so called absolute safety to obtain an operating license. The conceptual design of a permanent repository was determined by 1983, calling for a placement of copper-clad iron canisters in a granite bedrock about 1,650 feet underground, below the water table known as the KBS-3 method an abbreviation of kärnbränslesäkerhet, nuclear fuel safety [Wiki, 2011-2]. Space around the canisters will be filled with betonies clay. On June 3 rd 2009 Swedish government choose a location for deep level waste site at Östhammar, near Forsmark nuclear power plant. A legal and institutional framework of the Swedish radioactive waste management is described in [Berkhout, 1991]. France 59 nuclear reactors contributing about 75 per centum of its electricity. France has been reprocessing its spent reactor fuel since the introduction of nuclear power. France also reprocesses spent fuel elements for other countries, but the nuclear waste is returned to the country of origin. Disposal in deep geological formations is being studied by the French agency for radioactive waste management in underground research labs. Government in 1998 approved Meuse/Haute Marne Underground Research Lab for further consideration. Legislation was proposed in 2006 to license a repository by 2015, with operations expected in 2025. Moreover, a good perspective of the French waste management strategy for a sustainable development of nuclear energy is described in [Courtois, 2005]. Nuclear waste policy in Germany is the most controversial. With 17 reactors in operation, accounting for about 30 per centum of its electricity, Germanys planning for a permanent geologic repository began in 1974, focused on the salt dome Gorleben. The site was announ- ced in 1977 with plans for a reprocessing plant, spent fuel element management, and perma- nent disposal facilities at a single site. Plans for the reprocessing plant were dropped in 1979. In 2000, the federal government agreed to suspend underground investigations for three to ten years, and committed to ending its use of nuclear power, closing one reactor in 2003. Meanwhile spent fuel elements have been transported to interim storage facilities at Gorleben, Lubmin and Ahaus until temporary storage facilities can be built near reactor sites. Previously, spent fuel was sent to France or England for reprocessing, but this practice was ended in July 2005. Meanwhile the exploration of the salt dome Gorleben is carried on. Moreover, the legal and institutional framework of the German radioactive waste politics is described in [Berkhout, 1991; Wellmer, 1999]. Switzerland’s four nuclear reactors provide about 43 per centum of its electricity. ZWILAG, an industry-owned organization, built and operates a central interim storage facility for spent nuclear fuel elements and HLW, for conditioning LLW and for incinerating wastes. The Swiss program is currently considering options for the siting of a deep repository for HLW disposal, and for low & intermediate level wastes. Construction of a repository is not [...]... Radioactive, Toxic and Hazardous Wastes, John Wiley and Sons, ISBN 978-1-444-31937-8, New York Dyne, P J (1975) Managing Nuclear Waste AECL Technical Report AECL-5136, May 1975 ENS – European Nuclear Society (January 2011) Nuclear Power Plants in Europe, January 26, 2011, Available from: www.euronuclear.org/info/maps.htm, Access 26.01.2011 Ford, M.(2 010) Finland's nuclear waste bunker built to last 100 ,000 years,... http://en.wikipedia.org/wiki/KBS-3 Access 04.03.2011 330 Nuclear Power – Deployment, Operation and Sustainability YUCCA (2008 Radioactive Waste Repositories: Hanford Site, Yucca Mountain Nuclear Waste Repository, Natural Nuclear Fission Reactor Books LLC Publ ISBN-13-978-1157005278 14 Isotopic Uranium and Plutonium Denaturing as an Effective Method for Nuclear Fuel Proliferation Protection in Open and Closed Fuel Cycles Kryuchkov... -particles, 1/(gs) 8 101 1 2.3 108 7.9 104 1.2 104 Mean energy of -particles, MeV 5.3 4.76 4.4 4.19 Specific yield of spontaneous fission neutrons, 1/(g s) 1.3 5.02 10- 3 2.99 10- 4 1.36 10- 2 Fission cross-section (En  0.0253 eV), barns 77.15 0.465 583.2 1.2 10- 5 Table 2 Basic nuclear properties of main uranium isotopes 232U is a starting isotope for chain of radioactive decays, and some 232U decay products... (2.6 MeV and 1.8 MeV, respectively) that improves detectability of 232U-containing nuclear materials (Gilfoyle & Parmentola, 2001) and complicates radiation conditions, especially for any unauthorized actions Nuclear properties of main 232U decay products are presented in Table 3 212Bi) 334 Nuclear Power – Deployment, Operation and Sustainability Decay products Half-life 228Th Energy of -particles,... detail 3 Nuclear properties of 232U and 231Pa Basic nuclear properties of main uranium isotopes are presented in Table 2 (Reilly et al., 1991; OECD Nuclear Energy Agency, 1997) As it may be seen, some nuclear properties of 232U make it a valuable material for proliferation protection of uranium-based nuclear fuel 232U 234U 235U 238U Half-life, years 68.9 2.45 105 7.04 108 4.47 109 Specific yield of -particles,... investigated Thus, one has to investigate in particular the effectiveness of the geological and geotechnical barriers and design a coherent long term management of a higher activity radioactive waste concept 322 Nuclear Power – Deployment, Operation and Sustainability Fig 7 Laboratory version of the flame jet pump system injection head (with permission of Professors Lazar and Sekula, Technical University of... can be used as a nuclear charge but they may be produced only under neutron irradiation of natural uranium or thorium in nuclear reactors At present, nuclear reactors apply uranium fuels of various enrichments So, isotopic composition of uranium-based fuel for civilian NPP takes an intermediate position between 332 Nuclear Power – Deployment, Operation and Sustainability natural uranium and HEU Conversion... Applicability of Contemporary Deep-Sea Ecology and Reevaluation of Gulf of Mexico Studies, Final Report OCS Study MMS 2001-095 U.S 328 Nuclear Power – Deployment, Operation and Sustainability Dept of the Interior Minerals Management Service, Gulf of Mexico OCS Region Office, New Orleans, La 174 pp CGER (Commission on Geosciences, Environment and Resources) (1994) Drilling and Excavation Technologies for the... suitable even for export deliveries 338 Nuclear Power – Deployment, Operation and Sustainability 4.1 Isotopic denaturing of uranium as a way for creating an internal source of particles Along with progress in development of high-efficiency enriching technologies, potential threat of LEU diversion and re-enrichment up to the weapon-grade level excites more and more apprehensions These reasons indicate...314 Nuclear Power – Deployment, Operation and Sustainability foreseen in this century Research on sedimentary rock is presently carried out at the Swiss Mont Terri rock lab Great Britain has 19 operating reactors, producing about 20 per centum of its electricity It processes much of its spent fuel elements at Sellafield where nuclear waste is vitrified and sealed in stainless steel . withdrawn and run through the turbines controls the power level of the nuclear power plant reactor. Hence, nuclear power plants use nuclear fis- sion for producing electrical energy. Nuclear Power. 2 010; Lutze, 1988; Weber et al., 1995], and then placed inside corrosion-resistant containers. Spaces between waste packages Nuclear Power – Deployment, Operation and Sustainability 310. circles. Worldwide are 436 nuclear power plants in operation, and 47 under construction. 133 nuclear power plants are planned, and 282 are proposed. In total 898 nuclear power plants will run in the